Optical waveguides are used in a number of application areas, including telecommunications, sensing, illumination, endoscopy and imaging. Optical fibers are a class of waveguides, which are typically cylindrical in geometry and can be manufactured in lengths that are long compared to their diameter. Optical fibers can employ a variety of mechanisms to confine the light in the structure and conduct it along the fiber length. There are examples of fibers using total internal reflection (TIR) between a high-index core and a lower-index cladding, as well as fibers using photonic band gaps (PBG), which are structures that prohibit the propagation of light at certain frequencies to confine light to regions that do not prohibit propagation.